Finding the Fourth Proportional to 1,659.15, 2,487.89 and 781.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,659.15 : 2,487.89 = 781.38 : x
2. Step 2: Convert to fraction form
   1,659.15/2,487.89 = 781.38/x
3. Step 3: Cross multiply
   1,659.15x = 2,487.89 × 781.38
4. Step 4: Simplify right side
   1,659.15x = 1,943,989.44
5. Step 5: Solve for x
   x = 1,943,989.44/1,659.15
6. Step 6: Final answer
   x = 1,171.68